Toner resin composition and toner

#1. Field of the Invention

#The present invention relates in general to a toner resin composition and toner used in electrophotography and such, and more particularly to a toner resin composition and toner used in the so-called dry developing method for developing electrostatic charge images.

#2. The Prior Art

#Examples and Comparative examples of the present invention are shown below.

#30 weight parts of a vinyl-type copolymer with a peak molecular weight value of 500,000 obtained by polymerizing a mixture composed of 80 wt % styrene and 20 wt % N-butyl acrylate, 4 weight parts of the low-melting-point crystalline compound (A) shown in Table 1, 1 weight part of the block copolymer of polystyrene and polyolefin (a) shown in Table 2, and 100 weight parts of toluene were put into a flask and dissolved. After purging the inside of the flask with nitrogen gas, the temperature was raised to the boiling point of toluene. As toluene was refluxing and the mixture was being stirred, a mixture of 50 weight parts of styrene, 15 weight parts of N-butyl acrylate and 3.8 weight parts of benzoyl peroxide (polymerization starter) was dripped into it over a period of three hours to carry out the coexistent solution polymerization. After completion of the dripping, stirring continued with toluene refluxing for one more hour for maturation, and a low molecular weight polymer with a molecular weight peak value of 8,000 was polymerized.

#The temperature in the flask was then gradually raised up to 180° C. at a reduced pressure to remove toluene and obtain a resin. After cooling, this resin was crushed to obtain the toner resin composition of the present invention.